Processes And Systems For Laser Crystallization Processing Of Film Regions On A Substrate Utilizing A Line-Type Beam, And Structures Of Such Film Regions

ABSTRACT

Process and system for processing a thin film sample, as well as at least one portion of the thin film structure are provided. Irradiation beam pulses can be shaped to define at least one line-type beam pulse, which includes a leading portion, a top portion and a trailing portion, in which at least one part has an intensity sufficient to at least partially melt a film sample. Irradiating a first portion of the film sample to at least partially melt the first portion, and allowing the first portion to resolidify and crystallize to form an approximately uniform area therein. After the irradiation of the first portion of the film sample, irradiating a second portion using a second one of the line-type beam pulses to at least partially melt the second portion, and allowing the second portion to resolidify and crystallize to form an approximately uniform area therein. A section of the first portion impacted by the top portion of the first one of the line-type beam pulses is prevented from being irradiated by trailing portion of the second one of the line-type beam pulses.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/373,772, filed Mar. 9, 2006, which is a continuation of InternationalApplication Serial No. PCT/US04/030330, filed Sep. 16, 2004, publishedMar. 31, 2005, which claims priority from U.S. Provisional ApplicationSer. No. 60/503,361, filed Sep. 16, 2003, each of which are incorporatedby reference in their entireties herein, and from each of which priorityis claimed.

FIELD OF THE INVENTION

The present invention relates to techniques for processing of films, andmore particularly to location-controlled techniques for processingsemiconductor films using a line-type beam so as to obtain a substantialuniformity of certain regions of the thin films in which microstructures(e.g., thin-film transistor “TFT'” devices) can be situated.

BACKGROUND OF THE INVENTION

Semiconductor films, such as silicon films, are known to be used forproviding pixels for liquid crystal display devices. Certain prior artsystems utilize line-type beams which are shaped to have a particularline-shape. An exemplary illustration of the line-type beam pulse 200,and a profile thereof are illustrated in FIG. 4A. In particular, theline beam pulse 200 may defined by a length L and width W′. The profileof the line-type beam pulse 200 illustrated in FIG. 4A has a convex topportion 205, a large section of which has sufficient energy density tobe below a complete melting energy density threshold. This profile ofthe line-type beam pulse 200 also has a leading portion 210 and atrailing portion 215. The leading portion 210 has an energy densitybeginning from a low or negligible energy density level, continuing toreach a crystallization threshold, and ending below the complete meltingenergy density threshold so as to reach the convex top portion 205. Thetrailing edge portion 215 has an energy density starting from the edgeof the convex top portion 205 (which is at a sufficient energy below thecomplete melting energy density threshold), passing the crystallizationthreshold, and ending at the low or negligible energy density level. Thelength L of the line beam can be between 10 cm and 50 cm so as toirradiate a significant section of a thin film provided on a sample. Theconventional system generally use line beam pulses to irradiate the samesection of the sample over 10 times with the energy density which issomewhat below the complete melting threshold. In this manner, a moreuniform film may be attained, but the processing of such film isextremely slow. Indeed, 5 the systems which use such line-type beam 200are currently not suitable for quick processing of samples. In addition,when the edge portions (i.e., the leading and trailing edge portions210, 215) irradiate the corresponding sections of the thin film,non-uniformity may be created in these sections.

As shown in FIG. 4B, other conventional systems attempt to overcomethese problems associated with non-uniformity by continuously scanningdisplay areas 220,225 of the sample 180, until the entire area iscompletely irradiated. As shown in FIG. 5, this is generally performedby irradiating areas of the sample using successive pulses of theline-type beam 200, such that a significant portion of the areairradiated by a first pulse 300 of the beam 200 is subsequentlyirradiated by the next pulse 310. It follows that a sizable portion ofthe area of the sample irradiated by the pulse 310 is reirradiated bythe subsequent pulse 320. Also, a large portion of the area irradiatedby the pulse 320 is reirradiated by the next pulse 330, and so on. Theoverlap of the areas irradiated by the adjacent pulses is provided suchthat the distance between the adjacent pulses is the width of the topportion of the pulse divided by between 10 and 100, and preferablydivided by approximately 20.

It may be possible to reduce the non-uniformity of the irradiatedsections of the thin film sample by maintaining the energy density ofthe line-type beam pulse 200 to be above the complete melting threshold.In particular, as shown in FIGS. 6A and 6B, sections of a thin filmsample irradiated at an energy density above the complete meltingthreshold 250 form small polycrystalline grains compared to sections ofthe thin film sample irradiated at an energy density below the completemelting threshold. Between these sections, there is a narrow regionwhere grains are very large, due to near complete melting of the film.In addition, when the energy density is below the crystallizationthreshold, the irradiated area is amorphous.

It is conceivable to reduce the non-uniformity of the irradiatedsections of the thin film sample by maintaining the energy density ofthe line-type beam pulse 200 to be below the complete melting threshold.In particular, as shown in FIGS. 6C and 6D, sections of a thin filmsample irradiated with beam pulses 200 at a constant energy density thatis above the crystallization threshold and below the complete meltingthreshold 205′ have an approximately uniform grain size.

However, there are disadvantages to the use of these conventionalmethods. For example, when the irradiated areas of the thin film arerequired to be overlapped, the processing time of the entire sample isslow. This is because the sample is processed to ensure thereirradiation of significant parts of the previously irradiated areas ofthe thin film.

SUMMARY OF THE INVENTION

One of the objects of the present invention is to provide an improvedprocess and system which irradiate at least one thin film section of thesubstrate using a line-type beam pulses so as to at least partially meltthese sections, and without the irradiated areas being re-irradiated bythe following beam pulses. In this manner, the melted sections of thethin film sections resolidify to form substantially uniform crystallizedregions therein. Due to the uniformity of these regions of theresolidified thin film sections, it is possible to place the TFT devicesin such regions. Thus, the TFT devices situated in such manner wouldlikely have at least similar performance with respect to one another.Another object of the present invention is to continuously translate andirradiate one or more sections of the thin film sample (e.g., withoutstopping) such that the above-described uniformity is achieved in anaccelerated manner.

In one exemplary embodiment of the present invention, a process andsystem for processing a semiconductor thin film sample, as well as atleast one portion of the semiconductor thin film structure are provided.In particular, a beam generator can be controlled to emit successiveirradiation beam pulses at a predetermined repetition rate. Each of theirradiation beam pulses can be shaped to define at least one line-typebeam pulse, with the line-type beam pulses being provided for impingingthe film sample. These line-type beam pulses can include at least onepart which have an intensity sufficient to at least partially meltirradiated portions of the film sample. Thereafter, a first portion ofthe film sample is irradiated using a first one of the line-type beampulses to at least partially melt the first portion, with the irradiatedfirst portion being allowed to resolidify and crystallize. After theirradiation of the first portion of the film sample, a second portion ofthe film sample is irradiated using a second one of the line-type beampulses to at least partially melt the second portion, with theirradiated second portion also being allowed to resolidify andcrystallize. An emission of the second one of the line-type beam pulsesmay immediately follow an emission of the first one of the line-typebeam pulses. A profile of each of the line-type beam pulses may includea leading portion, a top portion and a trailing portion. For example, asection of the first portion impacted by the top portion of the firstone of the line-type beam pulses may be prevented from being irradiatedby trailing portion of the second one of the line-type beam pulses.

In another exemplary embodiment of the present invention, the firstportion of the film sample is irradiated by the top portion of the firstone of the line-type beam pulses, wherein the second portion of the filmsample is irradiated by the top portion of the second one of theline-type beam pulses. The top portion of each of the line-type beampulses may have energy density which is above a complete meltingthreshold. Each of the leading and trailing portions of the first one ofthe line-type beam pulses can irradiate a part of the first portion, andeach of the leading and trailing portions of the second one of theline-type beam pulses can irradiate a part of the second portion. Inaddition, each of leading and trailing portions of the first and secondones of the line-type beam pulses may include first and second sections.Each of the first sections of the leading and trailing portions of thefirst and second ones of the line-type beam pulses may include an energydensity which is sufficient to at least partially melt the respectivefirst portion and/or the respective second portion. Also, each of thesecond sections of the leading and trailing portions of the first andsecond ones of the line-type beam pulses can have an energy densitylower than a threshold level which is sufficient to at least partiallymelt the part of one of the respective first portion and the respectivesecond portion. The second portion can be irradiated after theirradiation of the first portion and after the film sample is translatedfor a particular distance with respect to an impingement by the beampulses of the first portion. The first section of the leading portion ofthe first one of the line-type beam pulses may have a first length, andthe first section of the trailing portion of the second one of theline-type beam pulses can have a second length. The top portion may havea third length. The particular distance can be greater than the sum ofthe third length and of the larger one of the first and second lengths.

According to still another embodiment of the present invention, dataassociated with locations on the film sample to be irradiated isreceived. Then, after the irradiation of the first portion and beforethe irradiation of the second portion, the film sample is translated fora particular distance with respect to an impingement by the beam pulsesbased on such received data. The irradiation beam pulses can be shapedby a mask to define the line-type beam pulses. In addition, the firstand second ones of the line-type beam pulses can at least partially meltthe respective first and second portions of the film sample.Furthermore, the film sample can be translated for the particulardistance with respect to an impingement by the beam pulses in a periodicmanner and also based on an irradiation frequency of the irradiationbeam generator. Also, the first and second portions of the film samplecan include pixel areas. In addition, the first and second portions caninclude areas, which are configured to situate thereon an active regionof at least one thin-film transistor “TFT” device.

The accompanying drawings, which are incorporated and constitute part ofthis disclosure, illustrate a preferred embodiment of the invention andserve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic block diagram of an exemplary embodiment of anirradiation system according to the present invention which allowsselected areas of a semiconductor thin film to be continuously scanned,at least partially melted and without re-irradiating these areas, in apredetermined controlled manner using a line-type beam;

FIG. 1B is an enlarged cross-sectional side view of the sample whichincludes the semiconductor thin film;

FIG. 2 is a top view of an exemplary embodiment of a mask according tothe present invention utilized by the system illustrated FIG. 1A, whichpatterns a beam so as to have a line-type shape for irradiating theselected areas of the semiconductor thin film;

FIG. 3 is an exemplary illustration of a continuous-motion irradiationof the entire semiconductor thin film using the system of FIG. 1A andthe mask of FIG. 2;

FIG. 4A is a cross-sectional profile of the line-type beam which can beshaped by optics of the system of FIG. 1A and/or patterned by the maskof FIG. 2, and may be used for irradiating the semiconductor thin filmaccording to a first exemplary embodiment of the present invention whichhas energy density above the complete melting threshold;

FIG. 4B is an illustration of a continuous scan processing of thesemiconductor thin film using conventional systems, which re-irradiatepreviously irradiated areas or apply beams whose energy density is belowa complete melting threshold;

FIG. 4C is a cross-sectional profile of the line-type beam according toa second exemplary embodiment of the present invention which has energydensity above the crystallization threshold and below the completemelting threshold;

FIG. 5 is an illustration of profiles of multiple line-type beams whichre-irradiate previously irradiated portions of the semiconductor thinfilm;

FIGS. 6A and 6B are examples of the results of irradiations of theconventional systems and methods when utilizing line-type beams whoseenergy densities are above the complete melting threshold;

FIGS. 6C and 6D are examples of the results of irradiations of theconventional systems and methods when utilizing line-type beams whoseenergy densities are between the crystallization threshold and thecomplete melting threshold;

FIG. 7 is an exemplary illustration of sequential movements of thesemiconductor film of a sample with respect to the pulses of theline-type beam shaped by the optics of the system of FIG. 1A orpatterned by the mask of FIG. 2 according to an exemplary embodiment ofthe present invention;

FIG. 8 is a cross-sectional profile of another exemplary line-type beamwhich can be shaped by optics of the system of FIG. 1A and/or patternedby the mask of FIG. 2, and which has either minimal or insignificantsloping edge portions;

FIG. 9A is an illustration of the two particular areas irradiated,re-solidified and crystallized areas corresponding to the areas of FIG.7 in which the entire TFT device is situated on the small uniformedgrained region formed through complete melting and re-solidificationaccording to the present invention;

FIG. 9B is an illustration of the two particular areas irradiated,re-solidified and crystallized areas corresponding to the areas of FIG.7 in which only the entire cross-section of the active region of the TFTdevice is situated in the small uniformed grained region formed throughnucleation, while other regions are provided over border areas betweenthe crystallized areas;

FIG. 10 is another exemplary illustration of sequential movements of thesemiconductor film of the sample with respect to the pulses of theline-type beam shaped by the optics of the system of FIG. 1A orpatterned by the mask of FIG. 2 according to another exemplaryembodiment of the present invention, in which the entire sample isirradiated in two passes; and

FIG. 11 is a flow diagram representing an exemplary processing procedureof the present invention under at least partial control of a computingarrangement of FIG. 1A using the exemplary techniques of the presentinvention of FIGS. 7 and 10.

DETAILED DESCRIPTION

It should be understood that various systems and methods according tothe present invention can be utilized to at least partially melt, thensolidify and crystallize one or more areas on a semiconductor thin film(e.g., silicon) using line-type beam pulses, while continuouslytranslating the sample and without re-irradiating the previouslyirradiated and resolidified areas to generate substantially uniformregions on the thin film. The exemplary embodiments of the systems andprocess to generate such areas, as well as of the resulting crystallizedsemiconductor thin films shall be described in further detail below.However, it should be understood that the present invention is in no waylimited to the exemplary embodiments of the systems, processes andsemiconductor thin films described herein.

Certain systems for providing a continuous motion SLS are described inU.S. patent application Ser. No. 09/526,585 (the “585 application”), theentire disclosure of which is incorporated herein by reference.Substantially similar systems according to the exemplary embodiment ofthe present invention can be employed to generate at least partiallyirradiated, solidified and crystallized portions of the semiconductorfilm described above in which it is possible to process the entiresemiconductor thin film in a controlled and accelerated manner with aline-type beam. In particular, the system according to the presentinvention can be used on a sample 170 which has an amorphous thin film(e.g., silicon) thereon that is irradiated by irradiation beam pulses topromote the melting, subsequent solidification and crystallization ofthe particular areas of the semiconductor thin film. As shown in FIG.1A. the exemplary system includes a beam source 110 (e.g., a LambdaPhysik model LPX-3151 XeCl pulsed excimer laser) emitting an irradiationbeam (e.g., a laser beam), a controllable beam energy density modulator120 for modifying the energy density of the laser beam, a MicroLas twoplate variable attenuator 130 (e.g., a device by MicroLas), beamsteering mirrors 140, 143, 147, 160 and 162, beam expanding andcollimating lenses 141 and 142, a beam homogenizer 144, a condenser lens145, a field lens 148, a projection mask 150 which may be mounted in atranslating stage (not shown), an eye piece 161, a controllable shutter152, a multi-element objective lens 163 for focusing a radiation beampulse 164 onto the sample 170 having the semiconductor thin film to beprocessed mounted on a sample translation stage 180, a granite blockoptical bench 190 supported on a vibration isolation and self-levelingsystem 191, 192, 193 and 194, and a computing arrangement 100 (e.g., ageneral purpose computer executing a computer program according to thepresent invention or a special-purpose computer) coupled to control thebeam source 110, the beam energy density modulator 120, the variableattenuator 130, the shutter 152 and the sample translation stage 180.

The sample translation stage 180 is preferably controlled by thecomputing arrangement 100 to effectuate translations of the sample 170in the planar X-Y directions, as well as in the Z direction. In thismanner, the computing arrangement 100 controls the relative position ofthe sample 170 with respect to the irradiation beam pulse 164. Therepetition and the energy density of the irradiation beam pulse 164 arealso controlled by the computing arrangement 100. It should beunderstood by those skilled in the art that instead of the beam source110 (e.g., the pulsed excimer laser), the irradiation beam pulse can begenerated by another known source of short energy pulses suitable for atleast partially melting (and possibly fully melting throughout theirentire thickness) selected areas of the semiconductor (e.g., silicon)thin film of the sample 170 in the manner described herein below. Suchknown source can be a pulsed solid state laser, a chopped continuouswave laser, a pulsed electron beam and a pulsed ion beam, etc.Typically, the radiation beam pulses generated by the beam source 110provide a beam intensity in the range of 10 mJ/cm² to 1 J/cm², a pulseduration (FWHM) in the range of 10 to 300 nsec, and a pulse repetitionrate in the range of 10 Hz to 300 Hz.

While the computing arrangement 100, in the exemplary embodiment of thesystem shown in FIG. 1A, controls translations of the sample 170 via thesample stage 180 for carrying out the processing of the semiconductorthin film of the sample 170 according to the present invention, thecomputing arrangement 100 may also be adapted to control thetranslations of the mask 150 and/or the beam source 110 mounted in anappropriate mask/laser beam translation stage (not shown for thesimplicity of the depiction) to shift the intensity pattern of theirradiation beam pulses 164, with respect to the semiconductor thin filmof the sample 170, along a controlled beam path. Another possible way toshift the intensity pattern of the irradiation beam pulse is to have thecomputing arrangement 100 control a beam steering mirror. The exemplarysystem of FIG. 1A may be used to carry out the processing of thesemiconductor thin film of the sample 170 in the manner described belowin further detail. The mask 150 can be used by the exemplary system ofthe present invention to well define the profile of the resulting maskedbeam pulse 164, and to reduce the non-uniformity of the adjacentportions and edge regions of the portions of the semiconductor thin filmwhen these portions are irradiated by such masked beam pulse 164 andthen crystallized.

As illustrated in FIG. 1B, a semiconductor thin film 175 of the sample170 can be directly situated on, e.g., a glass substrate 172, and may beprovided on one or more intermediate layers 177 there between. Thesemiconductor thin film 175 can have a thickness between 100 Å and10,000 Å (1 μm) so long as at least certain necessary areas thereof canbe at least partially or completely melted throughout their thickness.According to an exemplary embodiment of the present invention, thesemiconductor thin film 175 (e.g., an amorphous silicon thin film) canbe composed of silicon. germanium, silicon germanium (SeGe), etc. all ofwhich preferably have low levels of impurities. It is also possible toutilize other elements or semiconductor materials for the semiconductorthin film 175. The intermediary layer 177, which is situated immediatelyunderneath the semiconductor thin film 175, can be composed of siliconoxide (SiO₂), silicon nitride (Si₃N₄), and/or mixtures of oxide, nitrideor other materials that are suitable for promoting grain growth withinthe designated areas of the semiconductor thin film 175 of the sample170. The temperature of the glass substrate 172 can be between roomtemperature and 800° C. Higher temperatures of the glass substrate 172can be accomplished by preheating the substrate 172 which wouldeffectively allow larger grains to be grown in the irradiated,re-solidified, and then crystallized areas of the semiconductor thinfilm 175 of the sample 170 due to the proximity of the glass substrate172 to the thin film 175.

The semiconductor thin film 175 can be irradiated by the beam pulse 164which can be shaped using the mask 150 according to an exemplaryembodiment of the present invention as shown in FIG. 2. The exemplarymask 150 is sized such that its cross-sectional area is preferablylarger than that of the cross-sectional area of the beam pulse 164. Inthis manner, the mask 150 can pattern the pulsed beam to have a shapeand profile directed by one or more open or transparent regions of themask 150. The exemplary embodiment of the mask 150 shown in FIG. 2includes an open or transparent region 157 that has a substantially longand narrow shape. This shape is defined by an opaque or beam-blockingregion 155. The open or transparent region 157 (which may 10 have alength L and a width A) permit beam pulses to irradiate there-through toat least partially melt the areas of the semiconductor thin film 175that they impinge. Each of the beam pulses shaped by the mask 175 has ashape substantially corresponding to the shape of the open ortransparent region 157.

An example of such beam pulse 200 is shown in FIG. 4A, which illustratesa first exemplary profile of the beam pulse, along with particulardimensions of sections thereof, which can be shaped by the optics of thesystem illustrated in FIG. 1A and/or produced by the mask 150 of FIG. 2.In particular, the shaped-beam pulse 200 may have a particular width W′(e.g., 300 μm to 1.2 mm) and a particular length L′ (e.g. 10 cm to 50cm), both of which relating to the length L40 and the width W of theopen/transparent region 157 of the mask 150. In this manner, the beampulse 200 thus produced by, e.g., the mask 150 extends for the length Lto preferably process the entire length of the thin film sample 175. Theentire sample 170 can be irradiated by the beam pulses 200 of the beam164 as shown in FIG. 3, and described in further detail below. Theprofile 220 of the beam pulse 200 includes a top portion 205, a leadingedge portion 210 and a trailing edge portion 215, all of which canextend for a particular distance. The top portion 205 may extend for adistance A within which the energy density is at or above the completemelting threshold. This distance A can be between 200 μm to 1 mm. Theleading edge portion 210 can extend for a distance B1 (e.g., between 50μm and 100 μm), and the trailing edge portion 215 may extend for adistance B2 (e.g., also between 50 μm and 100 μm). The leading edgeportion 210 has a section with a length of B1P, which extends from thepoint of the crystallization threshold to the point of the completemelting threshold, and which can be approximately half the size of thelength B1. Similarly, the trailing edge portion 215 has a section with alength of B2P which extends from the point of the crystallizationthreshold to the point of the complete melting threshold, and which canbe approximately half the size of the length B2.

A second exemplary profile of the beam pulse 200 is illustrated in FIG.4C, which can also be shaped by the optics of the system illustrated inFIG. 1A and/or produced by the mask 150 of FIG. 2. In this secondexemplary embodiment, the energy density of the beam pulse 200 has aprofile 220 with an energy density that is below the complete meltingthreshold. In particular, this profile 220 includes a top portion 205, aleading edge portion 210 and a trailing edge portion 215. The topportion 205 of this embodiment extends for a distance C, within whichthe energy density is approximately constant. The distance C may bebetween 200 μm to 1 mm. The leading edge portion 210 can extend for adistance D1 (e.g., between 50 μm and 100 μm). and the trailing edgeportion 215 may extend for a distance D2 (e.g., also between 50 μm and100 μm). The leading edge portion 210 has a section with a length ofDIP, which extends from to the point when the energy density isapproximately constant to a lower point of the crystallizationthreshold. Similarly, the trailing edge portion 215 has a section with alength of D2P which extends from the point of the crystallizationthreshold to a higher point of when the energy density is approximatelyconstant.

As shown in FIG. 3, according to an exemplary embodiment of the presentinvention, the pulses 200 of the line-type beam 164 irradiate all rowsof the thin film 175 provided on the semiconductor sample 170 in acontrolled manner. For example, the computing arrangement 100 controlsthe beam source 110 to emit an initial beam so that the beam 164 (eithermasked by the mask 150 or shaped by the optics of the system) irradiateseach row of the semiconductor thin film 175 provided on the sample 170by translating the stage 180 on which the sample 170 is situated basedon the location of the rows of the sample 170, i.e., relative to thedirection of the line-type beam 164. In particular, the computingarrangement 100 has a memory arrangement (not shown) which has storedthereon the location of each of the rows of the semiconductor thin film175 which are to be irradiated by the beam pulse 200. Therefore, therelative motion of the sample 170 with respect to the line-type beam 164and the actuation of the beam source 110 are performed based on thelocations of these rows. Such irradiation of the semiconductor thin film175 by the line-type beam 164 is continued until all rows of thesemiconductor thin film 175 provided on the sample 170 are irradiated bythe line-type beam pulses 200 so that they re-solidify and formuniform-grained material areas. According to a preferred embodiment ofthe present invention, at least the areas in the rows of thesemiconductor thin film 175 which are intended to situatemicrostructures (e.g., TFT's) thereon are preferably irradiated with thetop portion 205 of the pulse 200 and fully melted so that these areas(e.g., pixels) can preferably be irradiated once by the convex topportion 205 of the pulse 200 shown in FIG. 4A. It is also possible toirradiate the semiconductor thin film 175 using the top portion 205′ ofthe pulse 200 illustrated in FIG. 4C. In this exemplary embodiment, thetop portion 205′ has the energy density that is below the completemelting threshold of the thin film 175, thereby only partially meltingthe thin film 175. Of course, sections of the leading and trailingportions 210, 215 of the embodiment of FIG. 4A and the portion 210′,215′ of the embodiment shown in FIG. 4C can also irradiate thesemiconductor thin film 175 in a similar manner, with certainlimitations as shall be described in further detail below.

FIG. 7 illustrates sequential translations of the thin film 175 of thesample 170 with respect to the pulses 200 of the line-type beam 164shaped by the optics of the system of FIG. 1A and/or patterned by themask of FIG. 2 according to an exemplary embodiment of the presentinvention. In this exemplary illustration of the irradiation of thesemiconductor thin film 175 provided on the sample 170, the sample 170is translated in a −Y direction with respect to the direction of theline-type beam 164. When the sample 170 is translated in this manner toa position such that the line-type beam 164 points at a first row 510 ofthe thin film 175, the beam source 110 is actuated by the computingarrangement 100 so that a first line-type beam pulse 410 irradiates andat least partially melts, using a beam pulse 200 as depicted in FIG. 4C,or preferably fully melts, using a beam pulse 200 as described in FIG.4A, one or more portions 511-519 at the first row 510 of thesemiconductor thin film 175. The profile and length of the firstline-type pulse 410 shown in FIG. 7 substantially corresponds to theprofile and length of the pulse 200 illustrated in FIG. 4A. It ispreferable for the width A of the convex top portion 205 of the firstpulse 410 to be wide enough to irradiate and completely melt the entirecross-sections of the portions 511-519. These portions can be designatedto place certain structures (e.g., TFTs) therein so that they can beused to define the pixels. The resolidified portions which are partiallymelted would likely possess smaller crystallized-grain regions, butinclude uniform material therein.

Upon the irradiation and at least partial melting of such portions511-519 using the top portion 205 of the profile 220′ of the embodimentshown in FIG. 4C in the first row 510 of the semiconductor thin film 175as described above, the melted portions 511-519 resolidify andcrystallize so that they have uniform crystal grain growth therein.According to another exemplary embodiment of the present invention andalso as mentioned above, the line-type beam 164 may have enough energydensity to fully melt (throughout its thickness) the entire row 510 ofthe thin film 175, or at least the portions 511-519 thereof using thetop portion 205 of the profile 220 of the embodiment shown in FIG. 4A.Such fully melted and re-solidified portions of the thin film 175 wouldhave crystal-grains provided therein, which generally do not depend onthe sensitivity of the fluence of the line-type beam 164. In thismanner, the negative effects of the energy density fluctuations of theof the line-type beam 164 on the uniformity of the resulting TFT devicesprovided in such re-solidified areas are minimized.

After the first row 510 is irradiated and either partially or fullymelted using the line-type pulse 410 as described above, the sample 170is translated in the −Y direction (via a control of the computingarrangement 100) so that the beam 164 impinges on a second row 520 ofthe semiconductor thin film 175 provided on the sample 170. As for thefirst row 510 and upon reaching the second row 520, the beam source 110is actuated by the computing arrangement 100 to generate a secondline-type pulse 420 which irradiates and either at least partially orfully melts one or more sections 521-529 of the second row 520 insubstantially the same manner as described above with respect to theirradiation of the first row 510. This translation of the sample 170 (sothat the impingement of the line-type beam 164 moves from the first row510 to the second row 520 of the semiconductor thin film 175) isexecuted for a distance D. The distance D can be also referred to apixel row periodicity since the translation of the sample 170 via thedistance D is performed for other rows of the sample 170.

It is preferable for this distance D to be pre-assigned such that thetrailing portion 215′ of the second line-type pulse 520 does not overlapthe leading portion 210′ of the first line-type pulse 510. For example,the distance D can be measured from a center of the top portion 205′ ofthe first pulse 410 to a center of the top portion 205′ of the secondpulse 420. It is possible, however, to have certain sections of thetrailing portion 215′ of the second line-type pulse 520 and of theleading portion 210 of the first line-type pulse 510 overlap oneanother. Such portions would preferably possess only the energydensities that are smaller than the crystallization threshold value.Thus; preferably, no portion of the subsequent pulse 200 of the profile220′ should overlap the section of the thin film 175 irradiated by thetop portion 205′ of the preceding pulse 200 of such profile for theexemplary embodiment of FIG. 4C. This is because the flat top portion205′ partially melts the thin film 175, and generates grains of uniformsize in such irradiated areas.

If any subsequent irradiation on this irradiated section takes place,uniformity of this area may be compromised. Similarly, if the beam pulse200 having the profile 220 of FIG. 4A is utilized, then similartranslation distance considerations exist, except that none of theportions of the profile 220 of the subsequent beam pulse 200 shouldoverlap the section of the film sample 175 that was irradiated by thetop portion 205 of the previous beam pulse 200. However, contrary to theuse of the beam pulse 200 of the embodiment of FIG. 4C, the energydensity of the top portion 205 is above the complete melting threshold,and thus no portion of the subsequent beam pulse should overlap thecompletely melted previously section of the thin film 175 so as to avoidnon-uniformity of such overlapped section due to the reirradiationthereof.

The sample 170 can then again be translated for the distance D in thesame manner as described above with respect to the translation of thesample 164 so as to irradiate the second row 520 of the semiconductorthin film 175. Upon such translation, the line-type beam 164 impingesthe third row of the thin film 175, and irradiates and partially meltsone or more portions thereof.

Thus, for the embodiment of FIG. 4A, the width B2 of the leading portion210 (or width B2P) plus the width B1 of the trailing portion 215 (orwidth B1P) should be smaller than the distance D. In this manner, theleading portion 210 of the second line-type pulse 410 and the trailingportion 215 of the second line-type pulse 420 would not overlap. For theembodiment of FIG. 4C, in a similar manner, the width D2 of the leadingportion 210′ (or width D2P) and the width D1 of the trailing portion215′ (or width D1P) should both be smaller than the distance D.

According to one exemplary embodiment of the present invention, thetranslation of the sample 170 with respect to the impingement thereof bythe beam 164 is performed continuously (e.g., without stopping). Thecomputing arrangement 100 can control the beam source 110 to generatethe corresponding pulses 200 based on a predefined frequency. In thismanner, it is possible to define the velocity V of the continuoustranslation of the sample 170 with respect to the impingement of thesemiconductor thin film 175 by the line-type pulses 410, 420, so thatthe respective rows 510,520 of the thin film 175 are accuratelyirradiated by the pulses. For example, this velocity V of thetranslation of the sample 170 can be defined as follows:

V=D×f _(laser)

where f_(laser) is the frequency of the laser. Thus, if the distance Dis 200 μm and the f_(laser) is 300 Hz, the velocity V can beapproximately 6 cm/sec, which can be a constant velocity.

According to another embodiment of the present invention, while thesample 170 does not have to be continuously translated with respect tothe impingement thereof by the beam 164, the actuation of the beamsource 110 can be controlled based on a positional signal provided bythe translation stage 180. This signal may indicate the position of thesample 170 relative to the position of the impingement thereof by theline-type beam 164. Based on the data associated with such signal, thecomputing arrangement 100 can direct the actuation of the beam source110 and the translation to the sample 170 to achieve an effectiveirradiation of specific portions (e.g., rows) of the semiconductor thinfilm 170. Thus, the location controlled irradiation of at least portionsof the semiconductor thin film 175 can be achieved using a line-typebeam, 164.

The description above for the line-type beam 164 has been directed to aGaussian-shaped beam pulse, the examples of which is illustrated inFIGS. 4A and 4C. According to yet another exemplary embodiment of thepresent invention, it is also possible to utilize a top-hat line-typebeam 250, the exemplary profile of which is illustrated in FIG. 8. Inparticular, this line-type beam 250 has the energy density, which isgreater than the complete melting threshold of the semiconductor thinfilm 175. It should be understood that the energy density of this beam250 can also be greater than or equal to the crystallization thresholdof the semiconductor thin film 175 or above the complete meltingthreshold. As shown in FIG. 8, the top hat line-type beam 250 generallydoes not have any leading or trailing portions, and thus the distance Dof the translation of the sample 170 does not have to be as great aswould be preferable for the Gaussian-type beam. The top-hat line-typebeam 250 can be generated using a mask that has a knife edge aperturesuch that the beam source 110 provides a laser beam, which is thenshaped by such a mask.

FIG. 9A shows an illustration of exemplary first and second irradiated,resolidified and crystallized portions 511 and 512 of the first row 510of the semiconductor thin film 175 illustrated in FIG. 7. In particular,FIG. 9A shows that the entire TFT devices 610. 620 can be situatedwithin the respective first and second portions 511, 512 of the firstrow 510. The first TFT device 610 situated in the first portion 511 ofthe first row 510 includes a gate 612, a drain 614, a source 616 and anactive region 618. Similarly, the second TFT device 620 includes a gate622, a drain 624, a source 626 and an active region 628.

FIG. 9B shows an another exemplary illustration of the first and secondirradiated, re-solidified and crystallized portions 511 and 512 of thefirst row 510 of the S semiconductor thin film 175, with the respectiveTFT devices 610′, 620′ provided thereon. In this exemplary embodiment,only respective active regions 618′, 628′ of the TFT devices 610′, 620′are provided within the respective first and second crystallizedportions 511, 512, while other portions of the TFT devices 610′, 620′are situated on the borders of the these portions 511, 512. Inparticular, the first TFT device 610′ includes an active region 618′which entirely situated in the first portion 511 of the first row 510,while a gate 612′, a drain 614′ and a source 616′ of this TFT device610′ overlap the borders of the first portion 511. Also, for the secondTFT device 610′, an active region 628′ thereof is entirely situatedwithin the respective second portion 512 of the first row 510, while agate 622′, a drain 624′ and a source 626′ of the second TFT device 620′are provided directly on the borders of such second portion 512. Itshould be understood that any one of the gate 612, 612′, 622, 622′,drain 614, 614′, 624, 624′ and source 616, 616′, 626, 626′ can beprovided on the first and second areas 511, 512 and the border regionsthereof.

It should be understood that the above description is equally applicablefor all portions 511-519, 521-529, etc. of the semiconductor thin film175. In addition, the above placement of the active regions 618, 628,618′, 628′ within the portions 511-19, 521-529, etc. is possible due tothe uniformity achieved using the exemplary system and process accordingto the present invention described herein.

FIG. 10 shows another exemplary illustration of sequential movements ofthe sample 170 by the translation stage 180 with respect to theimpingement of the pulses of the line-type beam shaped by the optics ofthe system of FIG. 1A or patterned by the mask of FIG. 2. In thisexemplary embodiment, the relative translation of the sample 170 withrespect to the impingement by the line-type pulses 410, 420 aresubstantially similar to the relative translation of the sampledescribed above with reference to FIG. 3.

However, the length of the line-type beam 164 in this embodiment isapproximately half the length L of the embodiment of the line-type beam164 of FIG. 3. For example, the profile of the line-type beam 164 shownin FIG. 10 can be 15 cm, irradiating the sample 170 which has a widthwhich is smaller than 30 cm. Accordingly, using such beam length, theentire sample 170 is irradiated in two passes. In particular, one halfof the sample 170 is irradiated in the manner described above withreference to FIG. 7 by, e.g., irradiating such half section of thesample 170 while translating the sample 170 in the −Y direction. Whenthe impingement of the line-type beam 164 completes the irradiation ofthe entire half section of the sample 170 (i.e., reaches an oppositeedge from which the irradiation began), the sample 170 is translated inthe −X direction, and second half section of the sample 170 isirradiated while translating the sample 175 in the +Y direction. Thus,the entire sample 170 can be irradiated by the line-type beam 164 in twopasses. It is also within the scope of the present invention to use theline-type beams which have shorter lengths, so that a larger number ofpasses are performed to completely process the sample 170.

FIG. 11 shows a flow diagram representing an exemplary processingprocedure of the present invention under at least partial control of thecomputing/processing arrangement 100 of FIG. 1A using the exemplarytechniques of the present invention provided in FIGS. 7 and 10. In step1000, the hardware components of the system of FIG. 1 A, such as thebeam source 110; the energy beam modulator 120, and the beam attenuatorand shutter 130 are first initialized at least in part by the computingarrangement 100. The sample 170 is loaded onto the sample translationstage 180 in step 1005. It should be noted that such loading may beperformed either manually or automatically using known sample loadingapparatus under the control of the computing arrangement 100. Next, thesample translation stage 180 is moved, preferably under the control ofthe computing arrangement 100, to an initial position in step 1010.

Various other optical components of the system are adjusted and/oraligned either manually or under the control of the computingarrangement 100 for a proper focus and alignment in step 1015, ifnecessary. In step 1020, the irradiation/laser beam 111 is stabilized ata predetermined pulse energy level, pulse duration and repetition rate.In step 1024, it is preferably determined whether each beam pulse 164has sufficient energy to at least partially melt (and preferably fullymelt) the irradiated portions of the semiconductor thin film 175 withoutoverheating. If that is not the case, the attenuation of the beam 111 isadjusted by the beams source 110 under the control of the computingarrangement 100 in step 1025, and step 1024 is executed again todetermine if the there is sufficient energy to at least partially meltthe portions of the semiconductor thin film 175.

In step 1027, the sample 170 is positioned to point the pulse 410 of theline-type beam 164 to impinge the first row 510 of the semiconductorthin film 175. Then, in step 1030, the respective row of thesemiconductor thin film 175 is irradiated and at least partially meltedusing a masked intensity pattern (e.g., using the mask 150 illustratedin FIG. 2). Thereafter, the irradiated row (and/or portions thereof) ofthe semiconductor thin film 175 are allowed to solidify and crystallize.In step 1045, it is determined whether there are any more rows of thesample 170 that is to be subjected to the irradiation, i.e., whether theirradiation, melting and resolidification of the semiconductor thin film175 has been completed. If not, in step 1050, the sample 175 istranslated so that the line-type beam impinges the next row of thesample 170, and the processing is returned to step 1030 for irradiatingof the current row of the semiconductor thin film 175. However, if instep 1045, it is determined that the irradiation and crystallization ofthe sample 170 is completed, and the hardware components and the beam111 of the system shown in FIG. 1A can be shut off, and the process isterminated in step 1055.

Using the system and process according to the present invention, it ispossible to obtain a significantly greater crystallization rate overthat of the conventional systems and processes. This crystallizationrate is provided as follows:

Crystallization Rate=Beam Length×Frequency of Laser×Pitch

For example, the crystallization rate effectuated by conventional systemand process is:

50 cm×20 μm×300 Hz=30 cm²/sec (for a 20 shot process)

In contrast, the crystallization rate afforded by the system and processaccording to the present invention is:

50 cm×300 μm×300 Hz 450 cm²/sec.

The foregoing merely illustrates the principles of the invention.Various modifications and alterations to the described embodiments willbe apparent to those skilled in the art in view of the teachings herein.For example, while the above embodiment has been described with respectto at least partial or full solidification and crystallization of thesemiconductor thin film, it may apply to other materials processingtechniques, such as micro-machining, photo-ablation, andmicro-patterning techniques, including those described in Internationalpatent application no. PCT/US01/12799 and U.S. patent application Ser.Nos. 09/390,535, 09/390,537 and 09/526,585, the entire disclosures ofwhich are incorporated herein by reference. The various mask patternsand intensity beam patterns described in the above-referenced patentapplication can also be utilized with the process and system of thepresent invention so long as a line-type beam pulses are generated. Itwill thus be appreciated that those skilled in the art will be able todevise numerous systems and methods which, although not explicitly shownor described herein, embody the principles of the invention and are thuswithin the spirit and scope of the present invention.

1-20. (canceled)
 21. A system for processing at least one section of athin film sample on a substrate, comprising: a processing arrangement,which when executing a computer program, is configured to perform thefollowing steps: (a) controlling an irradiation beam generator to emitsuccessive irradiation beam pulses at a predetermined repetition rate,(b) controlling a shaping of each of the irradiation beam pulses todefine at least one line-type beam pulse, wherein a profile of each ofthe line-type beam pulses includes a top portion, a leading portion anda trailing portion, the at least one line-type beam pulse being providedfor impinging the film sample; (c) controlling an irradiation of a firstportion of the film sample with at least the top portion of a first oneof the line-type beam pulses, to at least partially melt the firstportion, the irradiated first portion being allowed to resolidify andcrystallize to form approximately uniform areas therein, and (d) afterstep (c), controlling an irradiation of a second portion of the filmsample with at least the top portion of a second one of the line-typebeam pulses to at least partially melt the second portion, theirradiated second portion being allowed to resolidify and crystallize toform approximately uniform areas therein, wherein the processingarrangement controls an emission of the second one of the line-type beampulses to immediately follow an emission of the first one of theline-type beam pulses, wherein at least one section of the first portionof the film sample is prevented from being irradiated by the trailingportion of the second one of the line-type beam pulses.
 22. The methodaccording to claim 21, wherein the top portion of each of the line-typebeam pulses has an energy density which is above a complete meltingthreshold.
 23. The method according to claim 21, wherein the top portionof each of the line-type beam pulses has an energy density which isbelow a complete melting threshold.
 24. The system according to claim21, wherein the processing arrangement, when executing the computeprogram, controls each of the leading and trailing portions of the firstone of the line-type beam pulses to irradiate a part of the firstportion, and wherein each of the leading and trailing portions of thesecond one of the line-type beam pulses irradiates a part of the secondportion.
 25. The system according to claim 21, wherein each of leadingand trailing portions of the first and second ones of the line-type beampulses has first and second sections, wherein each of the first sectionsof the leading and trailing portions of the first and second ones of theline-type beam pulses has an energy density which is sufficient to atleast partially melt at least one of the respective first portion andthe respective second portion, and wherein each of the second sectionsof the leading and trailing portions of the first and second ones of theline-type beam pulses has an energy density lower than a threshold levelwhich is sufficient to at least partially melt at least one of therespective first portion and the respective second portion.
 26. Thesystem according to claim 21, wherein the processing arrangement, whenexecuting the computer program, performs step (d) after step (c) iscompleted and after the film sample is translated for a particulardistance with respect to an impingement by the beam pulses of the firstportion.
 27. The system according to claim 21, wherein the leadingportion of the first one of the line-type beam pulses has a firstlength, wherein the top hat portion of the first one of the line-typepulses has a second length, and the trailing portion of the second oneof the line-type beam pulses has a third length, and wherein theparticular distance is greater than the sum of the first, second andthird lengths.
 28. The system according to claim 21, wherein a sectionof the leading portion of the first one of the line-type beam pulsesthat has energy density that is between a complete melting threshold anda crystallization threshold and has a first length, wherein the topportion of the first one of the line-type pulses has energy density thatis above the complete melting threshold and has a second length, and thetrailing portion of the second one of the line-type beam pulses hasenergy density that is below the complete melting threshold and has athird length, and wherein the particular distance at least a larger ofthe sum of the first and second lengths and the sum of the second andthird lengths.
 29. The system according to claim 21, wherein the beampulse has a Gaussian shape.
 30. The system according to claim 21,wherein the first portion of the film sample is irradiated by the topportion of the first one of the line-type beam pulses, wherein thesecond portion of the film sample is irradiated by the top portion ofthe second one of the line-type beam pulses, wherein the top portion ofeach of the first and second ones of the line-type beam pulses has anapproximately constant energy density, and wherein the first and secondirradiated areas are partially melted by the respective first and secondones of the line-type beam pulses, wherein the top portion of each ofthe first and second ones of the line-type beam pulses has anapproximately constant energy density, and wherein the first and secondirradiated areas are partially melted by the respective first and secondones of the line-type beam pulses.
 31. The system according to claim 21,wherein no portion of the second one of the beam pulses irradiates anysection of the first irradiated and resolidified area.
 32. The systemaccording to claim 21, wherein the at least one section of the firstportion of the film sample that is prevented from being irradiated bythe trailing portion of the second one of the line-type beam pulsesincludes an active region.
 33. The system according to claim 21, whereinthe first and second portions of the film sample include active regionsof a thin film device.
 34. The system according to claim 21, wherein theirradiation beam pulses are shaped by a mask to define the line-typebeam pulses.
 35. The system according to claim 21 wherein the processingarrangement, when executing the computer program, is further configuredto perform the following steps: (g) after step (c) and before step (d),translating the film sample for a particular distance with respect to animpingement by the beam pulses in a periodic manner and based on afrequency of the irradiation of the irradiation beam generator.
 36. Thesystem according to claim 21, wherein the first and second portions ofthe film sample include pixel areas.
 37. The system according to claim21, wherein the first and second portions include areas which areconfigured to situate thereon an active region of at least one thin-filmtransistor “TFT” device.
 38. A system for processing at least onesection of a thin film sample on a substrate, comprising: a processingarrangement, which when executing a computer program, is configured toperform the following steps: (a) controlling an irradiation beamgenerator to emit successive irradiation beam pulses at a predeterminedrepetition rate, (b) controlling a shaping of each of the irradiationbeam pulses to define at least one line-type beam pulse, wherein aprofile of each of the line-type beam pulses includes a top portion, aleading portion and a trailing portion, the at least one line-type beampulse being provided for impinging the film sample, (c) controlling anirradiation of a first portion of the film sample with at least the topportion of a first one of the line-type beam pulses, to at leastpartially melt the first portion, the irradiated first portion beingallowed to resolidify and crystallize to form approximately uniformareas therein, (d) after step (c), controlling an irradiation of asecond portion of the film sample with at least the top portion of asecond one of the line-type beam pulses to at least partially melt thesecond portion, the irradiated second portion being allowed toresolidify and crystallize to form approximately uniform areas therein,wherein the processing arrangement controls an emission of the secondone of the line-type beam pulses to immediately follow an emission ofthe first one of the line-type beam pulses, wherein at least one sectionof the first portion of the film sample is prevented from beingirradiated by the trailing portion of the second one of the line-typebeam pulses (e) receiving data associated with locations on the filmsample to be irradiated, and (f) after step (c) and before step (d),translating the film sample for a particular distance with respect to animpingement by the beam pulses based on the received data.
 39. A sectionof a thin film sample provided on a substrate, comprising: a firstirradiated and crystallized portion; and a second irradiated andcrystallized portion which does not overlap the first portion, whereineach of the first and second portions are irradiated by line-type beampulses, wherein a profile of each of the line-type beam pulses includesa top portion, a leading portion and a trailing portion, the at leastone line-type beam pulse being provided for impinging the film sample,the at least one line-type beam pulses being provided for impinging thefilm sample, wherein the first portion is irradiated with at least thetop portion of a first one of the line-type beam pulses, to at leastpartially melt the first portion, the irradiated first portion beingallowed to resolidify and crystallize to form approximately uniformareas therein, wherein after the irradiation of the first portion, thesecond portion is irradiated with at least the top portion of a secondone of the line-type beam pulses to at least partially melt the secondportion, the irradiated second portion being allowed to resolidify andcrystallize to form an approximately uniform area therein, wherein anemission of the second one of the line-type beam pulses immediatelyfollows an emission of the first one of the line-type beam pulses, andwherein a section of the first portion impacted by the top portion ofthe first one of the line-type beam pulses is prevented from beingirradiated by trailing portion of the second one of the line-type beampulses.
 40. The system according to claim 38, wherein the top portion ofeach of the line-type beam pulses has an energy density which is above acomplete melting threshold.
 41. The system according to claim 38,wherein the top portion of each of the line-type beam pulses has anenergy density which is below a complete melting threshold.